JP2888685B2 - Method for producing food in sealed container and apparatus used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention precisely controls the supply amount of a mixed gas composed of an inert gas and steam for replacing air in an empty space in a container of a sealed container, so-called air in a head space. The present invention relates to a method for producing a food in a sealed container capable of producing a product of a certain quality and an apparatus used therefor.

[0002]

2. Description of the Related Art Generally, as a method of preventing or suppressing the daily change of flavor, color tone, etc. of food in a sealed container, air in a head space of the food in a sealed container is removed or reduced. Thus, there is known a method for preventing the above-described deterioration mainly caused by oxygen.

As such a method, for example, (1)
A method of filling a beverage at a high temperature (90 to 95 ° C) and closing the lid in that state, a so-called hot filling method (hot pack),
(2) After filling a beverage into a container, an inert gas such as nitrogen gas or carbon dioxide, or a mixed gas of an inert gas and steam is injected into a head space of the container, and air in the head space is injected. There is an undercover gassing method in which the lid is sealed while removing and replacing the lid. In addition,
(3) A method of sucking air in a container first (before filling the container with the beverage), injecting an inert gas or the like instead of the air, filling the content beverage, and sealing the lid (hereinafter, referred to as a lid) Liquid nitrogen is dropped after filling the content beverage for the purpose of imparting strength to the container in the case of a beverage in a thin can (a positive pressure can). The lid is sealed in a state where the gas is evaporated by the heat of the container and becomes nitrogen gas in the head space of the container, and as a result, the air in the head space is replaced with nitrogen gas (hereinafter, referred to as a liquid nitrogen dropping method). And so on.

[0004] Among these methods, the most commonly used is the undercover gassing method (2). The reason is that firstly, the air removal rate of the head space (generally, the oxygen content in the head space in the container after the lid is sealed is measured and calculated, rather than the hot filling method, (Hereinafter, referred to as a replacement rate). Also, as a second reason, the preliminary replacement method requires complicated and expensive remodeling of the filling mechanism or needs to be performed as a function of a dedicated machine for filling the specified container. However, the undercover gassing method can be implemented with a slight modification of the lid sealing device, and the equipment cost is extremely large compared to remodeling the filling mechanism significantly or purchasing a machine dedicated to filling specific containers. It is a small amount. Further, in the preparatory replacement method, the headspace portion of the container is exposed to the air after the preparatory replacement and before the lid is sealed, so that the air is mixed in, so the replacement rate is not so good.

[0005] In addition, in the liquid nitrogen dropping method, since the container is at a positive pressure, for example, when the retort sterilization step of high temperature and high pressure is required for the content beverage such as coffee, the container becomes at a high pressure during the process. There are problems such as rupture, and the type of content beverage is limited.

For the above reasons, the undercover gassing method is used as the most efficient method.
Also in this method, in the method of simply injecting the inert gas into the head space of the container, the degree of vacuum (negative pressure or reduced pressure) in the container is reduced, so that the content beverage has a high temperature and a high pressure as described above. If a sterilization step is required, the container does not burst during sterilization, but the lid expands and deforms, which not only results in a defective appearance and sealing performance, but also, for example, canned beverages It is said that it is not possible to use a sealability inspection device (referred to as a percussion machine, which cannot be inspected unless the pressure is 10 cmHg or more at the time of percussion (at the time of percussion)) at the time of percussion. Sometimes.

Therefore, the inert gas and the vapor are mixed, the mixed gas is injected into the head space of the container, the air in the head space is replaced with the mixed gas, the lid is sealed, and the mixed gas is removed. A method has been practiced in which the vapor inside condenses and dissolves in the beverage of the content to obtain an appropriate degree of vacuum and a replacement rate at the same time.

In this method, the state of the mixed gas injected into the head space of the container is controlled by adjusting the amount of the inert gas supplied to the gas mixer and the pressure of the supplied steam. The amount of inert gas is supplied to the gas mixer via a flow control valve with a flow meter, while the amount of steam is determined by the value of a pressure gauge provided in a steam pipe connected to the gas mixer.
The supply steam pressure is adjusted by a pressure reducing valve or the like. And, in fact, the supply amount of the inert gas is easy to stabilize, and it is almost stable at the first setting, so that the supply steam pressure is the main adjustment for producing the mixed gas. .

However, the pressure of steam, which is the main factor of adjustment, is a rough level in a normal pressure gauge (unit: Kg / cm ² ), for example, up to the first decimal place. In many cases, the resolution is limited to a value, and as a result, there is a problem that the state of the mixed gas cannot be controlled with high accuracy. In addition, since the mixed gas is continuously produced and injected, when changing the filling speed of the contents (assuming that the same substitution rate and degree of vacuum are obtained), the amount of the inert gas and the vapor pressure are also changed. You have to change it accordingly. Even in such a case, there is a problem that only a rough adjustment can be performed because the resolution is limited by a normal pressure gauge.

[0010] Further, in a normal production site, the supply source of the steam is distant from the gas mixer, or the supply destination from one steam source is diversified. There are many factors that make the pressure unstable, and as described above, the resolution of the pressure gauge is low, so even if the pressure fluctuates, the pressure cannot be read by the pressure gauge, and the state of the mixed gas changes. There is a problem that a product that deviates greatly from the above is produced.

Therefore, there is a possibility that the pressure gauge used for detection may be changed to a high-resolution one or a steam supply source may be improved by providing a dedicated steam supply source. The simplicity of implementation, which is one of the great advantages of the cover gassing method, is lost.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to fill a beverage container with a container, and to mix a beverage with steam and an inert gas. After replacing the air in the head space with the mixed gas, when closing the lid, the supply amount of the mixed gas can be accurately controlled, and the replacement ratio and the degree of vacuum in the container after the lid is sealed. It is an object of the present invention to provide a method for producing a food in a sealed container and an apparatus used for the same, which can easily control the product to a desired value and obtain a product of constant quality.

[0013]

An object of the present invention is to fill a container with contents, inject a mixed gas composed of an inert gas and steam, and to evacuate air in the head space of the container with the mixed gas. In a method for producing a sealed container food that seals the lid while replacing, the method for producing a sealed container food characterized by controlling the amount of steam by detecting the temperature of the mixed gas, and Means for supplying an inert gas, means for supplying steam, means for mixing the supplied inert gas and steam, and detecting the temperature of the mixed gas,
Means for controlling the amount of vapor and means for injecting the mixed gas and sealing the lid while replacing the air in the headspace of the container filled with the content with the mixed gas. This is achieved by a device used for the production of food in sealed containers.

That is, in order to keep the state of the mixed gas injected into the head space of the container constant,
Mainly, the steam pressure supplied to the gas mixer is detected and adjusted, but feedback control is performed by focusing on the temperature of the actually injected mixed gas, detecting the temperature, and adjusting the steam supply amount based on the temperature value. , The detection and control with high resolution can be easily performed, and the state of the mixed gas obtained thereby can be stabilized with high accuracy. The present inventors have found that the composition is well stabilized, and reached the present invention.

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view showing an embodiment in which the apparatus according to the present invention is implemented in a canned beverage. In the figure, reference numeral 1 denotes an inert gas pressure control valve for adjusting an inert gas amount;
Is an inert gas pressure gauge, 3 is an inert gas flow control valve with a flow meter for adjusting the flow rate of the inert gas, and 4 is an inert gas check valve. Reference numeral 8 denotes a steam pressure adjusting valve for adjusting the steam amount, 9 denotes an automatic steam amount adjusting valve for adjusting the steam amount, 10 denotes a steam pressure gauge, and 11 denotes a steam check valve.

Reference numeral 5 denotes a gas mixer for mixing an inert gas and steam. Reference numeral 6 denotes a temperature sensor for measuring the temperature of the mixed gas produced by mixing, and reference numeral 7 denotes a control device that converts information obtained by the temperature sensor into a control signal and controls the automatic steam flow control valve 9. Further, 14 is a filling machine for filling the contents beverage into the can, and 15 is a lid sealing device having means for injecting the mixed gas transferred to the head space portion of the can filled with the contents beverage. .

In the apparatus shown in FIG. 1, first, as means for supplying an inert gas, an inert gas transferred from a high-pressure inert gas supply source (not shown) is supplied to an inert gas pressure regulating valve 1. The inert gas pressure gauge 2 is used to adjust the flow rate of the inert gas mixed by the inert gas flow control valve 3 with a flow meter while monitoring the reduced pressure state of the inert gas. It is configured to supply an inert gas. Further, this means is provided with an inert gas check valve 4 for preventing backflow when supplying the inert gas to the gas mixer 5.

As means for supplying steam, the steam transferred from a high-pressure steam source (not shown) is depressurized by a steam pressure regulating valve 8 and the amount of steam is regulated by an automatic steam quantity regulating valve 9. Thus, it is configured to supply steam to the gas mixer 5. This means is provided with a steam pressure gauge 10 for monitoring the reduced pressure state of the steam and a steam check valve 11 for preventing a backflow when the steam is supplied to the gas mixer 5.

A gas mixer 5 is provided as means for mixing the inert gas supplied from the supply means with the vapor. Further, detecting the temperature of the mixed gas,
As means for controlling the amount of vapor, a temperature sensor 6 for measuring the temperature of the mixed gas is provided in the mixed gas flow path from the gas mixer 5 to the lid sealing device 15, and information obtained by the temperature sensor 6 is controlled. The control signal is sent to the device 7 and converted into a control signal. The control signal controls the automatic steam control valve 9. Note that the control device 7 may be a commonly used device.

Further, as described in Japanese Patent Application No. 3-102101 previously filed by the present inventor, for example, the lid sealing device 15 injects a conditioned gas mixture to form a head space of the container. The air inside is removed, and the lid is sealed. Further, when using a can as a container, the lid sealing device 15 includes a lid supplied from a can lid magazine and a can main body to which a beverage is filled and transported by a filling machine.
It is preferable to use a type in which the air in the head space is replaced while being conveyed at the same time with a gap through which the jetting gas passes, and at the same time, the lid is sealed. An example of such a lid sealing device 15 is an undercover gassing device as shown in FIG. This device is
As shown in FIG. 3, the can body 12 in which the beverage is filled in each position (dent portion) of the gassing turret 35.
Is supplied, while the gassing turret 35 rotates, the mixed gas is injected to replace the air in the head space of the can main body 12, the lid 40 is supplied, and the lid is tightened. Further, the liquid filling device 14 may be a commonly used device.

The production of a sealed canned beverage of the present invention using such an apparatus is carried out, for example, as follows. That is, the container main body 12 (an empty state in which the lid is not sealed) is continuously conveyed to the liquid filling device 14 at regular intervals by the conveyor 13. In the liquid filling device 14, a preparation liquid of milk coffee obtained by an ordinary method is stored in a closed hopper in a state where the temperature is raised to a predetermined temperature, and a can to which the preparation liquid is supplied is provided. Filling is performed in synchronism with 12. After the filling, it is transported by the transport conveyor 13 to the lid sealing device 15 provided with gas injection means. Here, the mixed gas produced by the gas mixer 5 is injected,
While replacing the air in the head space with the gas, the lid is sealed to obtain a product.

First, an inert gas necessary for the mixed gas to be injected into the head space is transferred from a high-pressure gas supply source, and the mixed gas to be injected is depressurized to a predetermined pressure by the inert gas pressure regulating valve 1. Then, the gas is adjusted to a predetermined flow rate by an inert gas flow control valve 3 with a flow meter, and then sent to a gas mixer 5 through an inert gas check valve 4. At this time, nitrogen gas, carbon dioxide gas or the like or a mixture thereof is used as the inert gas. On the other hand, the steam is transferred from a high-pressure steam supply source, reduced in pressure to a predetermined pressure by a steam pressure adjusting valve 8, and then sent to the gas mixer 5 through an automatic steam amount adjusting valve 9 and a steam check valve 11.

In the gas mixer 5, the inert gas and the vapor are mixed to produce a mixed gas. The produced mixed gas is sent to a lid sealing device 15 provided with a gas injection device, and the temperature is measured by a temperature sensor 6 on the way. The control device 7 calculates the difference between the information obtained by the temperature sensor 6 and the target value, and controls the automatic steam flow control valve 9 based on the result. That is, a temperature-adjusted mixed gas is completed.

The supply amount of the mixed gas is set in accordance with the degree of vacuum and the replacement ratio in the container after sealing the lid. That is, the temperature of the mixed gas to be supplied is set based on the desired degree of vacuum and the replacement ratio, and registered in the control device 7. Then, the difference from the actually detected temperature is calculated, the automatic steam amount adjusting valve 9 is adjusted, and the steam amount is controlled.

The container used in the present invention is not limited to a can, but may be a bottle made of glass, plastic or the like. The contents to be filled are not only beverages such as fruit juice, coffee, milk drinks, etc., but also solid foods etc. which can be packed.

[0026]

As described above, according to the present invention, when producing food in a sealed container, the inert gas and the steam used for removing air in the headspace of the container filled with the contents are used. Thus, the supply amount of the mixed gas consisting of the following can be controlled with high precision, and as a result, it has become possible to manufacture a product of constant quality.

According to the present invention, even when the flow rate of the inert gas is changed by changing the filling speed, the state of the mixed gas is detected and controlled based on the temperature. The degree of vacuum and the replacement ratio in the container can be easily controlled to desired values without searching for an appropriate supply steam pressure.

Hereinafter, the present invention will be described specifically with reference to examples. [Embodiment] Using the apparatus shown in FIG. 1 and the apparatus shown in FIGS. 2 and 3, which are enlarged views of the main part of FIG.
A cc steel can (3 pieces) was used. As the liquid to be filled, a general milk coffee liquid prepared by an ordinary method is used. The liquid temperature at the time of filling is 80 to 85 ° C., and the amount of the filled liquid is 2
The range was 40 to 250 cc. The liquid filling speed was 450 cans per minute, and this speed was synchronized with the lid sealing device. For the mixed gas injected into the headspace, the target value of the degree of vacuum was set to 25 cmHg, and the target of the replacement ratio was set to 95%. That is, as the inert gas, nitrogen gas was set at 200 NL / min, and the temperature of the mixed gas was set to be 75 ° C. at the center value to control the amount of steam. Also, usually, in the case of canned coffee production, after sealing the lid, it is necessary to perform retort sterilization,
This was also performed in the present embodiment. Table 1 shows the results obtained by the above method.

[Comparative Example] An experiment was carried out using a conventional apparatus as shown in FIG. In addition, container type, contents liquid, filling temperature,
The filling amount, the nitrogen gas flow rate, the filling speed, the target degree of vacuum in the container, and the like were all performed under the same conditions and the same target as in the example. First, an inert gas necessary for the mixed gas injected into the head space is transferred from a high-pressure gas supply source (not shown), and the pressure is reduced to a predetermined pressure by an inert gas pressure reducing valve 21. After being adjusted to a predetermined flow rate by the gas flow rate adjusting valve 23, the gas was sent to the gas mixer 26 through the inert gas check valve 24. On the other hand, the steam is transferred from a high-pressure steam supply source (not shown), is initially depressurized to a predetermined pressure (first stage) by a steam depressurizing valve 18, and further depressurized in a second stage by a depressurizing valve 19. , And sent to a gas mixer 26 through a steam check valve 25.

In the gas mixer 26, the steam and the inert gas were mixed to form a mixed gas. Adjustment of the mixed gas
Adjustment of the second-stage steam pressure reducing valve 19 was mainly performed. The resulting mixed gas was transferred to a lid sealing device provided with gas injection means. On the other hand, the can 27 as a container was transported to the liquid filling device 30 at regular intervals by the transport conveyor 28 in a state of an empty can (an empty state where the lid is not sealed). In the liquid filling device 30, a preparation liquid of milk coffee obtained by a conventional method is stored in a closed hopper in a state of being heated to a predetermined temperature, and the preparation liquid is supplied. Empty can 2
7 and filled. After filling, the conveyor 28
To the lid sealing device provided with gas injection means, where the mixed gas produced by the gas mixer 26 is injected, and the lid is sealed while replacing the air in the headspace with the gas. Got the product. After sealing the lid, retort sterilization was performed as in the example. Table 1 shows the results obtained by the above method.

[0031]

[Table 1]

From the above results, it can be seen that the variation in the degree of vacuum and the replacement ratio in the example is much smaller than the target value as compared with the comparative example.

Further, in the embodiment, the supply steam pressure does not change as a value read by the pressure gauge, but from the result of controlling the temperature of the mixed gas in the range of 74 to 76 ° C., the calorific value is calculated. Calculating the degree of the slight pressure change is as follows. The conditions for calculation are as follows:
It is assumed that a gas mixture of 0 ° C. is obtained.

[0034]

[Table 2]

Further, the difference between the specific heats of the nitrogen gas and the air is slightly different from the calorific value calculation, so that the constant of the humid air is used. Here, the amount of heat required for 30 ° C. air to become 70 ° C. is 200 (NL / Min) × 28.96 × (70−30) assuming that the specific heat at constant pressure is 0.24 (cal / g).
° C) x 0.24 = 2.482 (Kcal). On the other hand, from the table of humid air, the saturated steam amount at 30 ° C. and 70 ° C. (the amount that can exist as steam in the humid air) is 1 kg.
0.2763 kg at 70 ° C, 0.0271 at 30 ° C
8 kg. Since the amount of air is 258.571 g,
The amount of vapor that can be mixed in the humid air is 258.571５７1000 × (0.2763-0.02
718) = 0.064 Kg.

The enthalpies of saturated steam at 100 ° C. and 70 ° C. are 639.2 (Kcal / Kg) at 100 ° C. and 627.4 (Kcal / Kg) at 70 ° C., respectively. The amount of heat lost when the temperature reaches ° C is 0.064 (Kg) x (639.2-627.4) = 0.7552 (Kcal) (1), and the amount of heat lost by condensation is (X −0.064) Kg × 539 (2) Therefore, the calorie to be obtained is (1) + (2) = 2.4.
From 82 Kcal, X = 0.067 Kg.

Next, it is assumed that the two gases shown in Table 2 are mixed to form a mixed gas at 80.degree. Here, 30 ° C
The amount of heat required for the air to reach 80 ° C. is 200 (NL / Min) × 28.96 × (80−30) when the specific heat at constant pressure is 0.24 (cal / g).
° C) x 0.24 = 3.103 (Kcal). On the other hand, from the humid air table, the saturated steam amount at 30 ° C. and 80 ° C. (the amount that can exist as steam in humid air) is 1 kg.
0.546 kg at 80 ° C, 0.02718 at 30 ° C
Kg. Since the amount of air is 258.571 g, the amount of vapor to be mixed can exist in the humid air is: 258.571５７1000 × (0.546−0.027
18) = 0.1342 Kg.

The enthalpies of saturated steam at 100 ° C. and 80 ° C. are 639.2 (Kcal / Kg) at 100 ° C. and 631.5 (Kcal / Kg) at 80 ° C., respectively. The amount of heat lost when the temperature reaches ° C is 0.1342 (Kg) x (639.2-631.5) = 1.033 (Kcal) (3), and the amount of heat lost by condensation is (X −0.1342) Kg × 539 (4) Therefore, the calorie to be obtained is (3) + (4) = 3.1
X = 0.138 Kg from 02 Kcal.

From the above, it is considered that the vapor amount per hour is 8.28 kg / H when the mixed gas reaches 80 ° C. and 4.02 kg / H when the mixed gas reaches 70 ° C. Can be Here, in order to calculate how much the resolution of the temperature is relative to the resolution of the pressure, it is assumed that 8.28 Kg / H and 4.02 are set to the pipe of 5 mm in diameter at the same time.
Kg / If H of steam and flowed respectively, 80 ° C. In 0.4Kg / cm ² G, at 70 ℃ 0.1Kg / cm ²
G. Therefore, from that figure, the mixed gas 74-76 ° C
The change in pressure with respect to the temperature change in
0.28 kg / cm ² G, 1/100 kg / cm
^It can be seen that the change is a slight pressure change on the order of ² G. That is, the change in the supply amount of the mixed gas, which was difficult to detect with the resolution of the conventional pressure gauge, can be easily controlled by detecting the temperature.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of an apparatus according to the present invention.

FIG. 2 is an enlarged explanatory view of a main part of FIG. 1;

FIG. 3 is an explanatory view of a use state of the apparatus of FIG. 2;

FIG. 4 is an explanatory view showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inert gas pressure regulating valve 2 Inert gas pressure gauge 3 Inert gas flow regulating valve with flow meter 4 Inert gas check valve 5 Gas mixer 6 Temperature sensor 7 Control device 8 Steam pressure regulating valve 9 Automatic steam flow regulation Valve 10 Steam pressure gauge 11 Steam check valve 12 Can main body 13 Conveyor 14 Liquid filling device 15 Can lid sealing device provided with gas injection device 16 Product 17 Transport conveyor 35 Gassing turret 36 Mixed gas injection nozzle 40 Lid

Claims (2)

(57) [Claims] 1. A container is filled with contents, a mixed gas comprising an inert gas and a vapor is injected, and the lid is sealed while replacing the air in the head space of the container with the mixed gas. A method for producing food in a sealed container, wherein the amount of steam is controlled by detecting the temperature of the mixed gas. 2. A means for supplying an inert gas, a means for supplying steam, a means for mixing the supplied inert gas and steam, and detecting the temperature of the mixed gas to control the amount of steam. Means for discharging the mixed gas, and a means for sealing the lid while replacing the air in the headspace of the container filled with the content with the mixed gas, characterized by comprising: Equipment used for manufacturing.